White-Light-Emitting Materials for Organic Electroluminescent Devices

White emission is important for applying organic EL devices to full-color flat panel display and backlight for liquid crystal display. In order to obtain white emission, the use of a light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) (Zn(BTZ)₂ was known to emit white light with a broad electroluminescence. In this study, the electroluminescent characteristics of Be(BTZ)₂ and Mg(BTZ)₂, as well as Zn(BTS)₂ were investigated using organic electroluminescent devices with the structure of ITO/TPD/ Be(BTZ)₂, Mg(BTZ)₂, or Zn(BTZ)₂/Al. It was found that the device containing Be(BTZ)_2 showed the highest power efficiency.